Dr. Wen Xie publishes manuscript in Gastroenterology, entitled, “Inhibition of P53 sulfoconjugation prevents oxidativ hepatotoxicity and acute liver failure.” PLRC members contributing to this article: Dr. Xiaochao Ma, Dr. Paul Monga, Dr. Aatur Singhi. Dr. Pengfei Xu also contributed to this manuscript.

Wen Xie, MD, PhD
Xiaochao Ma, PhD
Paul Monga, MD
Aatur D. Singhi, MD, PhD


Background & aims: Sulfoconjugation of small molecules or protein peptides is a key mechanism to ensure biochemical and functional homeostasis in mammals. The PAPS synthase 2 (PAPSS2) is the primary enzyme to synthesize the universal sulfonate donor 3′-phosphoadenosine 5′-phosphosulfate (PAPS). Acetaminophen (APAP) overdose is the leading cause of acute liver failure (ALF), in which oxidative stress is a key pathogenic event, whereas sulfation of APAP contributes to its detoxification. The goal of this study is to determine whether and how PAPSS2 plays a role in APAP-induced ALF.

Methods: Gene expression was analyzed in APAP-induced ALF in patients and mice. Liver-specific Papss2 knockout mice using Alb-Cre (Papss2ΔHC) or AAV8-TBG-Cre (Papss2iΔHC) were created and subjected to APAP-induced ALF. Primary human and mouse hepatocytes were used for in vitro mechanistic analysis.

Results: The hepatic expression of PAPSS2 was decreased in APAP-induced ALF in patients and mice. Surprisingly, Papss2ΔHC mice were protected from APAP-induced hepatotoxicity despite having a decreased APAP sulfation, which was accompanied by increased hepatic antioxidative capacity through the activation of the p53-p2-Nrf2 axis. Treatment with a sulfation inhibitor also ameliorated APAP-induced hepatotoxicity. Gene knockdown experiments showed that the hepatoprotective effect of Papss2ΔHC was Nrf2-, p53- and p21-dependent. Mechanistically, we identified p53 as a novel substrate of sulfation. Papss2 ablation led to p53 protein accumulation by preventing p53 sulfation, which disrupts p53-MDM2 interaction and p53 ubiquitination, and increases p53 protein stability.

Conclusions: We have uncovered a previously unrecognized and p53-mediated role of PAPSS2 in controlling oxidative response. Inhibition of p53 sulfation may be explored for the clinical management of APAP overdose.